Question: $\left(8x + 8\right)\left(-5x + 10\right) = \ ?$
Solution: $= 8x \cdot \left(-5x + 10\right) + 8 \cdot \left(-5x + 10\right)$ $= \left( 8x \cdot -5x \right) + \left( 8x \cdot 10 \right) + \left( 8 \cdot -5x \right) + \left( 8 \cdot 10 \right)$ $= -40x^2 + \left( 8x \cdot 10 \right) + \left( 8 \cdot -5x \right) + \left( 8 \cdot 10 \right)$ $= -40x^2 + \left( 80x - 40x \right) + \left( 8 \cdot 10 \right)$ $= -40x^2 + 40x + \left( 8 \cdot 10 \right)$ $= -40x^2 + 40x + 80$